GK rails in a pedal?

[nshuman]

S

Hey Frank,

Just as a note the GK 700RB-II and 1001RB-II have a separate 50W amplifier that drives the horns on GK cabs with the crossover at 5kHz. This keeps the highs clean and free of the clipping that comes from pushing the power amp.

And for what it's worth I thought my 700RB sounded better when pushed with GK cabs than other tweeter loaded cabs.

v9, complete with crossover blend

 

[mbelue]

It was my understanding that the poweramp of the later models 700rb and 1000rb were different then the earlier 400rb&800rb.

 

[boomertech]

with R3 (1K) in series with the output transformer's primary to lug 4 and using a 10K pot for VR2, there's definitely more level, but it still has a severe top end roll off, at from 800hz-1K (just a guess on the freqs) as if a Pbass's tone control is rolled all the way down.

Can you run a spectrum analysis? If you can, remember to keep the input level down so we are not looking at amp distortion.

-Frank

 

[boomertech]

Hey Frank,

Just as a note the GK 700RB-II and 1001RB-II have a separate 50W amplifier that drives the horns on GK cabs with the crossover at 5kHz. This keeps the highs clean and free of the clipping that comes from pushing the power amp.

And for what it's worth I thought my 700RB sounded better when pushed with GK cabs than other tweeter loaded cabs.

Thanks for the info! That only complicates things more.

-Frank

 

[boomertech]

S



v9, complete with crossover blend

Totally NOT funny!!!!!!! J/K

-Frank

 

[boomertech]

It was my understanding that the poweramp of the later models 700rb and 1000rb were different then the earlier 400rb&800rb.

Which ones are supposed to give better 'rails' sound? Earlier or later?

-Frank

 

[boomertech]

Totally NOT funny!!!!!!! J/K

-Frank

If we get to V9, John will drive across the country just to stab me with his soldering iron.

-Frank

 

[Jared Lash]

Which ones are supposed to give better 'rails' sound? Earlier or later?

-Frank

I never directly A/B'd them but from what I remember the 400RB and 700RB-II sounded very similar when pushed, though it was much easier to get that sound with the 400.

As for the 1001RB-II I don't know that I ever got the "rails" tone out of it since that amp has so much headroom.

If we get to V9, John will drive across the country just to stab me with his soldering iron.

-Frank

 

[mbelue]

Which ones are supposed to give better 'rails' sound? Earlier or later?

-Frank

What's the "best" bass for metal?
I don't have experience with the latter models but I have run both a 400rb and an 800rb to their limits into an Ampeg 810 and an 800rb Peavey 215D.
Both experiences were defining moments in my bass-gear-nerd-life.
I'd say either amp into the Ampeg was the " rails sound ". That'd be what I call the rails tone. Wish I could comment on the newer amps.

The 215d was different, more aggressive and IMO better.

No idea what either would sound like separate from the influence from a cabinet. I haven't used them with any clean/clear cabinets.

 

[boomertech]

with R3 (1K) in series with the output transformer's primary to lug 4 and using a 10K pot for VR2, there's definitely more level, but it still has a severe top end roll off, at from 800hz-1K (just a guess on the freqs) as if a Pbass's tone control is rolled all the way down.

I just calculated the inductance of the primary coil at 3.9H and then put that into the simulator and WOW! This amp hates large inductance, even with the series 1K... the response basically takes a nose dive beyond 5KHz.

I need to try and negate that effect with a zobel. Didn't you mention before that you own an LCR bridge? If you do please measure the primary and secondary inductance with the opposite coil un-loaded.

-Frank

 

[boomertech]

What's the "best" bass for metal?
I don't have experience with the latter models but I have run both a 400rb and an 800rb to their limits into an Ampeg 810 and an 800rb Peavey 215D.
Both experiences were defining moments in my bass-gear-nerd-life.
I'd say either amp into the Ampeg was the " rails sound ". That'd be what I call the rails tone. Wish I could comment on the newer amps.

The 215d was different, more aggressive and IMO better.

No idea what either would sound like separate from the influence from a cabinet. I haven't used them with any clean/clear cabinets.

Thanx! I was worried that I was working with the wrong amp.

-Frank

 

[johnk_10]

I just calculated the inductance of the primary coil at 3.9H and then put that into the simulator and WOW! This amp hates large inductance, even with the series 1K... the response basically takes a nose dive beyond 5KHz.

tell me about it. here's the RTA of bypassed (GREEN), engaged thru VR1 (violet), and VR2 (BLUE):

I need to try and negate that effect with a zobel. Didn't you mention before that you own an LCR bridge? If you do please measure the primary and secondary inductance with the opposite coil un-loaded.

-Frank

I have an accurate inductance meter so i'll measure it now. so you want the primary measured between pins 2 & 4 , and the secondary measured between pins 5 & 8 with 6&7 connected with everything else out of the circuit?

 

[boomertech]

Can you run a spectrum analysis? If you can, remember to keep the input level down so we are not looking at amp distortion.

-Frank

I tried a few things and I'm taking the tranny off of the V5 schematic. I will post a schematic of a simple driver circuit that works with this tranny that can either be installed in this amp simulator or be used as a separate box.

-Frank

 

[boomertech]

tell me about it. here's the RTA of bypassed (GREEN), engaged thru VR1 (violet), and VR2 (BLUE):

I have an accurate inductance meter so i'll measure it now. so you want the primary measured between pins 2 & 4 , and the secondary measured between pins 5 & 8 with 6&7 connected with everything else out of the circuit?

Yes, sir... exactly 2-4 and 5-8.

-Frank

 

[johnk_10]

primary 2&4: 3.667H
secondary 5&8 (with 6&7 jumpered): 364.9H

 

[boomertech]

tell me about it. here's the RTA of bypassed (GREEN), engaged thru VR1 (violet), and VR2 (BLUE):

I have an accurate inductance meter so i'll measure it now. so you want the primary measured between pins 2 & 4 , and the secondary measured between pins 5 & 8 with 6&7 connected with everything else out of the circuit?

Was the tranny connected when you took the VR1 plot?

-Frank

 

[johnk_10]

I tried a few things and I'm taking the tranny off of the V5 schematic. I will post a schematic of a simple driver circuit that works with this tranny that can either be installed in this amp simulator or be used as a separate box.

-Frank

I don't have a problem with that.

 

[johnk_10]

Was the tranny connected when you took the VR1 plot?

-Frank

yep.

thru my amp, it didn't change anything in VR1's sound with or without the tranny connected.

 

[boomertech]

primary 2&4: 3.667H
secondary 5&8 (with 6&7 jumpered): 364.9H

365H on the secondary?

-Frank

 

[johnk_10]

yep, and checked it four times with same result. but that's with a 120Hz test freq.

with a 1K test freq (the only other test frq that I have)
primary is: 1.1H
and secondary is: 5.3H

so 1K is probably the better of the two test freqs.